The present invention relates to suspension systems for vehicles. In particular, the present invention is a torsion bar suspension system for an oscillating axle assembly of an articulated vehicle.
Torsion bar suspension systems for axle assemblies on a vehicle are generally known. U.S. Pat. No. 4,360,221 to Wagner discloses one such torsion bar axle suspension system for a tractor unit. The tractor unit includes an axle assembly suspended from a frame by a pair of shock absorbing members. A torsion bar is rotatably mounted to the frame, transverse to the longitudinal extent of the tractor unit. A pair of rods are rigidly attached to each end of the torsion bar. Opposite ends of the rods are connected directly to the axle assembly by universal joints which along with the pair of shock absorbing members support the axle assembly. Equal vertical movement of each end of the axle assembly is dampened by the shock absorbers and is not impeded by the rotatable torsion bar. Unequal vertical movement of the axle assembly ends causes the rods to apply a torsional force to the ends of the torsion bar. The torque resistance of the bar restrains the unequal vertical movement of the axle assembly ends. However, the range of unequal movement between the axle assembly ends is somewhat restricted.
It is evident that there is a continuing need for improved suspension systems for off road vehicles. Specifically, there is a need for a torsion bar axle suspension system of efficient design which permits a wider range of axle movement. The torsion bar axle suspension system should also act to transfer weight to the front of the vehicle to cushion vehicle ride during road travel.